1. Field of the Invention
The present invention is directed to technology for an intercom network.
2. Description of the Related Art
Intercom systems are widely used in various venues to allow communications between users. For example, personnel at performing art venues such as theaters and concert halls, as well as television studios, sports events, houses of worship, and schools, often use intercom equipment to communicate with each other. The personnel talk to each other via portable user stations (e.g., belt-pack devices connected to a headset), which rely on a master station to control and power the intercom system.
Traditionally, intercom systems have used analog signaling over cabling to communicate voice and control data between user stations. A two-wire party line system utilizes two wires of a cable, such as a microphone cable, to allow users to listen concurrently to a single conversation. A four-wire matrix system utilizes a transmit pair and a receive pair for the audio to and from a user station to provide point-to-point communications. In practice, cables with six to eight wires may be used in an intercom system in which two or four wires carry data and the remaining four wires carry audio. In each case, an additional ground wire or shield is also typically provided.
Recently, digital intercom systems have been developed in which user stations are connected via computer networking components such as CAT-5 cable. CAT-5 cable is commonly used in a structured wiring system in which cables are installed in a building in a permanent manner. However, such digital intercom systems do not allow the easy retrofitting of existing analog intercom networks with digital equipment to provide full featured, multi-channel digital communications over existing cabling.